Automotive vehicles commonly employ a suspension system connected between the road wheels and the body of the vehicle. Some vehicles employ an adjustable suspension that is adjustable to a plurality of ride control modes to vary the stiffness of the vehicle suspension. For example, the suspension may be adjusted to vary the shock absorption stiffness to any one of a firm (stiff) mode, an intermediate (normal) mode, and a plush (soft) mode. The various ride control modes allow the vehicle suspension to be adjusted to suit the particular needs of the passengers, depending on the conditions of the roadway and the passengers' comfort level, to thereby enhance the vehicle driving experience.
In order to select a ride control mode, the vehicle operator may manually enter the desired mode, or the vehicle may automatically change modes based on sensed conditions. According to one adjustable suspension system, a change in selection of the ride control mode changes the size of an orifice in a fluid flow path within each of the shock absorbers associated with the rear and/or front suspension of the vehicle. The change in the size of the orifice, in turn, adjusts the hydraulic fluid flow rate within the shock absorber which changes the stiffness of the shock absorber and therefore changes the suspension stiffness.
Conventional shock absorbers typically have a limited operating life, and therefore may need to be replaced when they no longer function properly. In order to determine if a shock absorber needs to be replaced, the conventional diagnostic testing approach typically involves a technician applying force to the vehicle fender, or elsewhere on the vehicle body, while the suspension is set to a first ride mode, and visually detecting the rocking movement response of the vehicle. The technician then selects a different ride mode and repeats the visual inspection. If the visual inspection detects a sufficient difference in vehicle rocking between the different modes, the shock absorber is determined to operate adequately. In an insufficient difference is detected, the suspension is determined to be defective. The conventional suspension testing approach therefore involves subjective interpretation by the technician which may not be consistently reliable.
It is therefore desirable to provide for an accurate test procedure for testing the ride control of suspension components on a vehicle to determine whether the ride control adjustment is functioning properly. In addition, it is desirable to provide for a test procedure for testing vehicle suspension components that does not require subjective interpretation by a technician.